Knockdown carpenter&#39;s square.



A. A. HARVIE.

KNOGKDOWN GARPENTERS SQUARE.

APPLIOATION -FILED FEB.3, 1912.

Patented Dec. 31,1912.

ALBERT A. HARVIE, OF OTTU'IVIWA, IOWA.

KNOCKIDOWN GARPENTERS SQUARE.

Specification of Letters Patent.

Patented nec.l31,1912.

Application filed February 3, 1912. Serial No. 675.335.

To all whom it may concern:

Be it known that I, ALBERT A. HARVIE, a citizen of the United States, residing at Ottumwa, in the county of llapello and State of Iowa, have invented certain new and useful Improvements in Knockdown Carpenters Squares, of which the following is a specification.

This invention vrelates to an improved form of carpenters square of such construction that the tongue can be removed from the blade in an extremelysimple manner, but nevertheless of such construction that when the tongue and blade are assembled they will be held firmly and rigidly and will be accurately positioned with respect to each other.

One of the main objects of the invention is to so construct the tongue and blade that when they are disassembled each will comprise merely a straight bar of metal, so that the two parts can be easily packed into a carpenters tool boX or other carrier.

Another object is to provide a novel form of locking means, whereby the tongue and blade will not only be held rigidly together but will be instantaneously and accurately positioned, both to secure proper angular relation between them and to position the tongue lengthwise of its dimension accurately with respect tothe blade. By this I mean that the end of the tongue shall project exactly the proper distance from the edge of the blade.

Another object is to so construct the parts.

that by merely turning one or more screws of the lock, the aforementioned accurate positioning shall be secured, and so that at the same time a clamping effect will be obtained, so that the parts may be clamped together with the same degree of force, re-

gardless of any slight wear which may take place, because the screw or screws may always be rotated until tight.

@ther objects and uses Ywill app-ear from a detailed description of the invention, which consists in the features of construction and combination of parts hereinafter described and claimed.

In the drawing, Figure 1 shows a top view of t-he face of my improved square, the tongue and blade being assembled and hav ing their end portions broken away; Fig'. 2 shows a top view of the inner end of the tongue; Fig. 3 shows a top view of the inner end of the blade; Fig. 4 shows a section taken on line 4.-4 of Fig; 1, looking in the directionV of the arrows; and Fig. 5 shows a section taken on line 5 5 of Fig. 1, looking in the direction of the arrows.

In the drawing, the tongue is designated by the numeral 6 and the blade bythenumeral 7. The blade is provided across the upper face of its inner end with a groove or slot 8 adapted to receive the end portion 9 of the tongue. This groove has its outer edge face'lO undercut, as shown more particularly in Figs. 4 and 5, the edge face V11 of the end of the tongue being correspondingly beveled, so that when the two elements are set together the tongue cannot be raised unless at the same time it be allowed to move sidewise. The edge face 12 of the groove is beveled or slanted substantially parallel to the edge face 10 thereof, and the edge face 13 of the tongue is correspondin gly undercut. By this constructiomif the face le of the tongue be forced downwardly into the groove, the tongue will at the same time be forced sidewise so as to insure a tight engaging of the edge face 11 of the tongue into the dovetailed edge face 10 of the groove. Now, in order to secure abetter clamping, and-in order to give the parts a certain amount of spring action, the surface of the groove is preferably arched or rounded a certain amount, as shown in Figs. i and 5, so that the central portion 15 of the groove shall be higher than its sides `1G and 17. At the same time the end of the tongue should be of such width with respect to the `groove that its edge faces 11 and 13 will clamp against the corresponding edge faces 10 and 12 of the groove before the lower surface 18 of the tongue contacts the surface `16 of the groove. By thus proportioning the parts, a certain amount of spring action can be secured and the tongue can be brought into firm and accurate register' with the gr'oove, until t-he edge faces of the tonguev and groove may have worn in service to a considerable extent, so that the surfaces 16 and 1S shall ultimately come into contact.

In other words, by thus proportioning the' parts, the same degree of accuracy and the same amount of clamping force can be secured, even though the parts wear to a con` Sider-able extent.

Obviously, any suitably formed clamping means may be adopted" for drawing the end of the tongue down intov the groove. In the present instance, I adopt screw-threaded studs, designated 19 and 2O respectively, which thread into the blade at a Vpoint alongside of the groove and have their heads 21 beveled outwardly to such an eX- tent that they may overlie Vthe edge face l2 of the groove. Each stud is provided with a hole 22, into which may be seated a key of suitable form to rotate the studand thus clamp the end of the tongue into the groove. Now, if each stud were formed with its head completely circular, it would be necessary to practically remove the studs before the tongue could be withdrawn vfrom the groove.

Inv order to simplify the process of setting up the square, or knocking it down, I cut away a portion 23 of the bevel of each stud, so that by rotating the studs into the position shown in Fig. 3 simply a partial rotation, the tongue can be immediately Withdrawn without having to completely remove the studs. I .also provide means for accurately spacing or positioning the tongue, so that its markings will occupy a predetermined distance from the edge 24 of the blade. To this end I cut the grooves 25 in the edge of the tongue so that the latter must be properly positioned in theV groove before the studs can be rotated to lock the parts together, as unless such positioning is effected it will be impossible to rotate the studs. Therefore, the studs perform a three-fold purpose: they serve to hold the end of the tongue in the groove; they serve to clamp the parts together; and they also serve to accurately position the tongue within the groove and to prevent its withdrawal therefrom in an endwise direction. v

In order to provide a flush edge 26 at the point where the edge of the tongue lines up with the groove, I provide a' shoulder 27 in they tongue. By this means, the two elements, when assembled, will constitute a perfectly accurate square or other instrument, although when disassembled each element will be virtually a straight bar of metal. f

It will be seen that the head of each screw has that portion which overlies the tongue beveled, so that as the screw is rotated it serves not only to clamp the tongue into the groovebut also tends to force the tongue sidewise, and thus make the undercut of the groove still more effective to holdV the two members solidly together.

While I have herein designated the member as the tongue and the member 7 as the blade, still` it would be evident that the terminology might be reversed, or that the mechanical arrangement might` be reversed, in either of which cases the groovel or slot would be formed in the tongue instead of in the blade.V In either case the mechanical arrangement and operation would be substantially the same as that herein shown and described. Y

I claim;

1l In a device of the class described, the combination of a blade, having a single socket fo-rmed in one of its surfaces, and having opposite edge faces of said socket Vundercut and beveled respectively in substantially parallel planes, a tongue having a single portion adapted to seat into the socket of the blade and having opposite edge faces ofsaid portion beveled and undercut to seat against the undercut and beveled' faces of the socket respectively, and

means for clamping the undercut edge face of the tongue toward the beveled edge face of the socket of the blade, to thereby force the tongue sidewiseV to bring its beveled edge face into solid engagement with the undercut edge face of the socketv of the blade, substantially as described.

2.`In a device of the class described, the combination ofa blade having a socket eX- tending in from one surface' and having parallel edge surfaces of said socket undercut and beveled respectively in substantially Vparallel planes, a tongue having a portion adapted to seat into said sockety and having parallel edge faces beveled and undercut to engage the undercut and beveled edge faces of the socket respectively, and means for clamping the undercut edge face of the tongue toward the beveled edge face of the socket of the bladeV to thereby exert a side pressure on the tongue to force its beveled edge face securely against the undercut edge face ofthe socket of the blade, substantially as described. Y

3.V In a device of the class described, the combination of a blade having a single socket extending inwardly from one of its surfaces and having an undercut edge face and a beveled edge face, a tongue having a single portion adapted to seat in the socket ofthe blade and having edge faces beveled and'undercut to correspond with the undercut and beveled edge faces of the socket of the blade respectively, and abev-y eled headed member screw-threaded into the blade and having a beveled portion of its head overlying a portion of the side of the tongue adjacent the undercut edge face of the same to force said edge face toward the beveled edge face of the socket of the blade and to simultaneously exert a side pressure on the tongue for forcing the same sidewise to bring its beveled edge face into firm contactV with the undercut edge face of the blade, substantiallyV as described.

` ALBERT A. HARVIE.

- Witnesses: V

THOMAS A. BANNING, Jr., EPHRAIM BNNING.

copies of thisiniteiits.may be obtained for ve cents each, by addressing' the Commissioner of Patents,

" "Washington, D. C. -Y 

